/*
 * WS281x LED Strip Driver for PRU1
 * Vixy's Jaw LEDs - 24 LEDs (12 per side)
 * 
 * Original Pin: P8_45 = pr1_pru1_pru_r30_0 (Mode 5) - LOCKED BY HDMI
 * Alternative: We use PRU0 with different memory offset instead
 *              since all PRU1 pins are HDMI locked on this image
 * 
 * This firmware is kept for reference but we'll use a combined
 * PRU0 firmware that handles both strips sequentially.
 */

#include <stdint.h>
#include <pru_cfg.h>

#define LED_PIN     0
#define NUM_LEDS    24

/* WS2812 timing at 200MHz */
#define T0H     70
#define T0L     160
#define T1H     140
#define T1L     120

/* Shared memory offset for jaw data (after mood strip) */
#define SHARED_MEM  0x00010100  /* 256 bytes after PRU0 data */

volatile uint8_t *shared = (volatile uint8_t *)SHARED_MEM;
volatile register uint32_t __R30;

static inline void delay_cycles(uint32_t cycles) {
    while (cycles--) {
        __asm(" NOP");
    }
}

static void send_bit(uint8_t bit) {
    if (bit) {
        __R30 |= (1 << LED_PIN);
        delay_cycles(T1H);
        __R30 &= ~(1 << LED_PIN);
        delay_cycles(T1L);
    } else {
        __R30 |= (1 << LED_PIN);
        delay_cycles(T0H);
        __R30 &= ~(1 << LED_PIN);
        delay_cycles(T0L);
    }
}

static void send_byte(uint8_t byte) {
    for (int i = 7; i >= 0; i--) {
        send_bit((byte >> i) & 1);
    }
}

void main(void) {
    CT_CFG.SYSCFG_bit.STANDBY_INIT = 0;
    __R30 &= ~(1 << LED_PIN);
    
    while (1) {
        if (shared[1] == 1) {
            uint8_t num = shared[0];
            if (num > NUM_LEDS) num = NUM_LEDS;
            
            for (int i = 0; i < num; i++) {
                uint8_t g = shared[4 + i * 3 + 0];
                uint8_t r = shared[4 + i * 3 + 1];
                uint8_t b = shared[4 + i * 3 + 2];
                send_byte(g);
                send_byte(r);
                send_byte(b);
            }
            
            __R30 &= ~(1 << LED_PIN);
            delay_cycles(10000);
            shared[1] = 0;
        }
    }
}